Follow-up valve



July l0, 1956 B. N. ASHTON ET AL FoLLow-UP VALVE l Filed Feb. 2. 1952 INVENTORS BENJAMIN N. ASHTON EUG E V. BARK HEN VON PEss BY i I THEIRATTORNEYS.

United States Patent O FoLLow-UP VALVE Benjamin N. Ashton and Eugene V. Barkow, Kingston, and Henry Von Pessler, Cottekill, N. Y., assignors to Electrol Incorporated, Kingston, N. Y., a corporation of Delaware Application February 2, 1952, Serial No. 269,664

2 Claims. (Cl. 74-388) nisms have been suggested heretofore. Usually, the prior art mechanisms include a differential gear device, one part of which can be operated manually or by power means to open the valve to start a motor while another part of the differential is operated by an element driven by the motor to close the valve so that during a predetermined movement of the manual or power controlled element, the motor driven element will be displaced through a proportional distance.

The present invention provides a greatly simplified means for controlling the valve to enable such a follow-up operation of a hydraulic motor or the like. In general, it includes a rotary member mounted on the control stem of a valve which is connected by threads or camming means to another relatively rotatable but non-axially movable member which is rotated by the driven element or motor of the system. In this way, rotation of one of the elements in one direction will cause the valve to open while the rotation of the other element by the driven member or motor will cause the valve to close and thereby stop the motor.

For a better understanding of the present invention, reference may be had to the accompanying drawing in which:

Fig. 1 is a View in section through a typical valve and follow-up control embodying the present invention; and

Fig. 2 is a schematic showing of a typical hydraulic system utilizing the control and disclosing its connection in the hydraulic system.

Referring to Fig. 1 of the drawing, the control mechanism may be applied to a four port selector valve generally of the type disclosed in the Ashton United States Patent No. 2,349,069, dated May 16, 1944. The valve includes a casing 11 in which are mounted a series of four valve poppets 12, 13, 14 and 15 by means of which flow of liquid from a pressure port 16 through the motor and to a return port 17 can be controlled. The poppets 12 and 13 control the ilow to and from a line port 18 while the poppets 14 and 15 control the flow of liquid through the line port 19. The poppets are displaced from their seats by means of a slidable cam shaft 20 which is provided with tapered cam surfaces 21, 22, 23 and 24 cooperating with the inner ends of the poppets 12, 15, 14 and 13, respectively. Downward movement of the cam shaft 20 causes the poppets 12 and 14 to be unseated thereby permitting liquid to flow from the pressure port 16 to the line port 18 and permitting liquid to flow from the line port 19 to the return port 17.

Upward movement of the cam shaft 20 unseats the poppets 15 and 13 so that the flow is reversed, that is, the

Patented Y July Y1 0, l

line port 19 is connected to the pressure port 16 while the line port 18 is connected to the return port 17.

While the invention is described with reference to a poppet-type valve, it will be understood that any other type of valve having an axially slidable control shaft or valve may be used.

The cam shaft 20 is normally biased upwardly, as viewed in Fig. 1 by means of a spring 25 bearing against a ring 26 in the end of the bore 27 in which the cam shaft is received and the upper end of a recess 28 in the lower end of the cam shaft. In the position shown, all of the poppets are seated. The spring 25 must be powerful enough to unseat the valves 13 and 15, when the cam shaft is not restrained against upward movement.

The cam shaft 20 is retained in the bore 27 by means of a retaining ring 30 at the upper end of the casing. The ring 30 has fingers 31 and 32 engaging in grooves 33 and 34 in the cam shaft to prevent its rotation and limiting its longitudinal movement. The upper end 3S of the cam shaft is of reduced cross section and it extends through an externally threaded sleeve or worm 40 which carries at its upper end an actuating lever 41. The lever 41 is mounted on a non-circular extension 42 of the worm 40 and is xed Ythereto by means of a threaded plug 43 threaded into the upper end of the extensio-n 42. The worm 40 is rotatable and the plug 43 engages the upper end 35 of the cam shaft.

The threads 44 on the worm 40 mesh with complementary internal threads 45 on a nut or sleeve 46 which is concentric with the worm 40 and the shaft 35. The nut 46 is provided with a flange 47 at its lower end which is received in a retaining ring 48 fixed to the end of the casing 11 so that the nut 46 is rotatable but cannot move axially. The nut 46 also carries an actuating arm 49 which may be threaded on the exterior of the nut and locked in position by means of a screw 50. While the Worm 40 and nut 46 are shown as being provided with threads it will be understood that other types of inclined plane or camming elements may be used to produce axial movement of the cam shaft 20.

The construction described above permits movement of the cam shaft in either direction from its neutral position by rotation of the worm 40 and return of the cam shaft to its neutral position by rotation of the nut 46 in the same direction. Thus, if the nut 46 is kept stationary and the worm 40 is rotated, the latter will be screwed into or out of the nut 46. The cam shaft 2lb follows the axial movement of the worm 40 because the spring 25 holds the end 35 of the cam shaft against the plug 43 at all times. In this way, the spring 2S takes up all the backlash in the Worm 40 and nut 46. In like fashion, if the worm 40 remains stationary, rotation of the nut 46 will move the Worm 40 endwise toward or away from neutral position.

The follow-up action of the threaded elements is best shown schematically in Fig. 2. In a hydraulic system disclosed therein, a pump 51 is provided to supply pressure through a conduit 52 to the pressure port 16 of the valve 10. Liquid is supplied to the pump from a reservoir 53 and the reservoir is connected also by a conduit 54 to the return port 17 of the valve 10. Ther line ports 18 and 19 are connected to opposite ends of a hydraulic jack 55, the piston 56 of which is connected to a movable element such as a wing flap 57 pivoted at 58. The system may also be provided with an unloading valve 59 which returns liquid through the conduit 60 to the reservoir 53 when the valve 10 is in its neutral or closed position.

Assuming that the lever 41 is a manually actuated control handle, the valve 10 may be connected to the jack 55 so that movement of the handle 41 in a clockwise direction will open the valve to admit liquid under pressure through the port 19 to the lower end of the jack 55. The liquid pressure will move the piston upwardly and liquid 3 above the piston will be returned through the port 18 to the reservoir 53.

The control member 49 may be connected in any suitable way such as by means of the link 62 and the lever 73 to the wing ap so that upon the clockwise movement of the wing ap resulting from upward movement of the piston, the lever 49 will be rotated in a clockwise direction thereby returning the cam shaft 35 to its neutral position and closing all of the valves.

Counterclockwise movement of the lever 41 will result in a reversal of the above-described operation so that the valve will be closed after the flap S7 moves counterclockwise to a position corresponding to the displaced position of the handle 41.

It will be understood, of course, that the new follow-up control may be used in many dierent types of follow-up systems and the nut and worm elements may be actuated in accordance with the requirements of such systems. Accordingly, the above-described embodiment of the invention should be considered as illustrative and not as limiting the scope of the following claims.

We claim:

1. A follow-up mechanism for a control unit having a casing and a slide member therein to control another device, comprising a pair of concentric, telescoping sleeves having cooperating threaded portions for moving them endwise relatively on relative rotation, an end closure at one end of the inner sleeve, means biasing said slide mernber into the inner sleeve and into engagement with said end closure for axial movement therewith, means supporting the other sleeve for rotation relative to said casing and retaining it against axial movement relative thereto, and means to rotate said sleeves selectively to move said slide member endwise.

2. A follow-up mechanism for valve units arranged to be opened selectively so as to reverse the direction of ow of liquid to a device actuated by such ow comprising a casing, a slidable cam shaft member in said casing, a rst rotatable sleeve member having external threads thereon and an axial recess having a closed outer end, means urging an end of said slidable member into said recess and against said closed end, a second internally threaded sleeve member threaded on said first sleeve member and rotatable relative thereto, means supporting said second threaded member for rotation on and retaining it against axial movement relative to said casing, and a member to rotate one or' said first and second members to move said slidable member endwise in one direction, and a member to rotate the other of said members to move the slidable member in a direction opposite to said one direction.

References Cited in the le of this patent UNITED STATES PATENTS 1,161,157 Radiguer Nov. 23, 1915 2,586,990 Poitras Feb. 20, 1952 FOREIGN PATENTS 108,544 Sweden Nov. 23, 1943 

